Are Male Sperm Counts Declining Over Time?

By: Dr. John Schnorr

Approximately one third of all patients with infertility have a male factor infertility component. There has been a considerable amount of discussion and research in the reproductive endocrinology community about whether or not male sperm counts have been declining over the last 40 to 50 years. The studies that have been done are confounded by different geographic regions which all tend to have varying sperm concentrations, and changes in the way we assess sperm quality over time.

A recent publication in Human Reproduction Update in November of 2017 used meta-analysis data from semen counts performed in North America, Europe, Australia and New Zealand over the last 40 years. This study has demonstrated a 52% decline in sperm concentration and 59% decline in the total sperm count over the last 40 years. This has resulted in a 1.4% decline per year in the sperm concentration and a 1.6% decline per year in the total sperm count. Other studies have demonstrated similar trends.

Clearly declining sperm counts can be a marker of declining fertility, which is one of our concerns with the declining sperms counts. The greater concern, however, is that sperm quality has been suggested as a biologic marker for a long term morbidity and mortality of men. A Danish study published in October of 2017 studied 5,370 men with male factor infertility over the last 30 years. Those men with male factor infertility were found to have a 1.5 fold increased risks for all-cause hospitalization, and on average were hospitalized seven years earlier for their first hospitalization than men with normal semen analysis. The most common causes for hospitalization were cardiovascular disease and diabetes.

When investigating the causes for the decline in sperm count over the last 40 years, it is thought that chemicals within our environment, such as pesticides, lead and fire retardants can be a cause. There is also a strong link between male factor infertility and obesity which is steadily increasing across the world. Other likely causes include increased alcohol consumption and marijuana use.

Hopefully further studies can help us pinpoint the exact causes of the decline in sperm counts so that those can be corrected. In the meantime, avoiding chemical exposure and “moderation in all things” appears to be the best path toward improving men and women’s health.